Aim: Our aim was to establish measurements of subcutaneous fat area ratio (SFAR) and visceral fat area ratio (VFAR) in the early second trimester using magnetic resonance imaging (MRI) in an obese pregnant cohort.
Methods: Obesity was defined as pre-pregnancy body mass index of 25.0 or more. One hundred and twelve obese pregnant women with a singleton pregnancy gave written informed consent between April 2007 and April 2010. For determining the most suitable MRI slice level, four women lacking MRI slices at the level of L2-3 or L3-4, and two women upon whom MRI was performed at 14 and 19 weeks were excluded, and the remaining 106 women were analyzed. We developed a novel method for calculating SFAR and VFAR at 15-18 weeks using a T₁-weighted spin echo sequence with fluid-attenuated inversion recovery for MRI where fat shows high signal intensity.
Results: MRI slices just above the uterine fundus at 15-18 weeks of gestation never included either the fundus or liver, but the other three slices always included either the liver or the uterus. In addition, the mean value of VFAR just above the uterine fundus was significantly larger than those at L2-3, L3-4 and navel position (47.3 ± 1.1% vs 37.3 ± 1.0%, 45.1 ± 1.2%, 45.6 ± 1.2%, respectively [P < 0.001]).
Conclusion: The most suitable MRI slice level for calculating SFAR and VFAR may be just above the uterine fundus in pregnant women at 15-18 weeks of gestation. The evaluation of clinical significance of visceral adiposity for gestational diabetes mellitus is warranted.
Keywords: magnetic resonance imaging; obesity; pregnancy; second trimester; visceral adiposity.
© 2014 The Authors. Journal of Obstetrics and Gynaecology Research © 2014 Japan Society of Obstetrics and Gynecology.